


Hold On

by nihilistshiro



Category: Voltron: Legendary Defender
Genre: Alpha Keith (Voltron), Alpha/Beta/Omega Dynamics, Alternate Universe, Anal Fingering, Anal Sex, Blow Jobs, Bottom Shiro (Voltron), Bottom Shiro Week 2019, Creampie, Explicit Sexual Content, Galra Shiro (Voltron), Knotting, M/M, Mating, Mutual Pining, Omega Shiro (Voltron), SHEITH - Freeform, Size Difference
Language: English
Status: Completed
Published: 2019-01-21
Updated: 2019-01-21
Packaged: 2019-10-13 18:42:12
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,813
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17493218
Author URL: https://archiveofourown.org/users/nihilistshiro/pseuds/nihilistshiro
Summary: Shiro and Keith have worked well together on many missions with the Blade of Marmora, always maintaining a professional balance, despite their secret pining for each other. But when a mission goes south and they end up stranded together, the tension between them snaps. (Keith is half-human, half-Galra like in canon and Shiro is Galra).





	Hold On

**Author's Note:**

> This was initially inspired by [@Jotakorium's](https://twitter.com/Jotakorium?lang=en) Galra!Shiro AU and then [this tweet from @Crimson_Poison.](https://twitter.com/Crimson_Poison/status/1085268621998338049)
> 
> Title inspired by the song 'Hold On' by the Internet.

_ “I know it’s not ideal, but I’m afraid you’re stuck there for a few more quintants.” _

The fuzzy hologram of Kolivan’s face glitched as it displayed from Shiro’s bionic arm. It was a miracle he managed to patch through a signal after their craft was destroyed.

Shiro and Keith had been sent on a mission on the other side of the galaxy, and halfway through they were ambushed by a small band of pirates. They were alive, but their ship was badly damaged during their escape. They crashed on a moon in the Thaldycon system and managed to piece together a camp, mostly thanks to a forgiving rock face with a decent cave.

The Blade was sending a rescue party, but it would take them a while to get there.

“No worries, general. Keith and I can hang tight.” Shiro said.

_ “Good. Save your energy. The rescue team is on their way.” _

“Understood.”

The transmission ended and Shiro sighed, rubbing a purple hand over his hair. Another few quintants in Keith’s company was likely to kill him. The alpha was attractive, smart, and fearless–even if he was almost ten years younger. Being in Keith’s presence did something to Shiro’s insides that he didn’t understand

Shiro was thirty-six, well past the age that most others had mated and began having pups. In fact, on Daibazaal it was taboo not to be mated by thirty, which stuck in the back of Shiro’s mind like a thorn.

Keith brought dormant feelings bubbling to the surface, feelings that Shiro had tried to stifle as each year passed him by. It was unprofessional and inappropriate to be fantasizing about what it would be like to mate with his junior officer. He had overseen Keith’s training with the Blades, and falling for him didn’t take place until later on when they started fighting side by side.

As far as Shiro knew, the alpha was oblivious, but that wasn’t going to last much longer. Normally, Shiro took suppressants to dim his omega pheromones, but they were about to wear off. Once they did, Keith would be privy to Shiro's deepest secret. Shiro's scent would betray his willingness–his desire–and Shiro would promptly die of embarrassment.

He didn’t know why he worried, though. There was still no way someone like that would go for someone like him. Someone well past their prime.

He sighed and made his way to the fire Keith was sitting by, his hands cupped near the flames, and forced the dangerous thoughts away.

Keith turned when Shiro approached.

“What did Kolivan have to say?”

“Says we’ll be stuck here a lot longer than we initially planned.” Shiro was exhausted, having stayed awake through the night to re-establish the comms link while Keith got some sleep. It was nighttime again, the sun setting over a ridge of orange rock.

“Can’t be helped I suppose.”

“Yeah,” Shiro said, sinking down across from Keith.

“You okay?”

“M'fine. Just tired.”

“You should get some rest. I'll stay up and tend the fire for a while.”

“Thanks,” Shiro said, stretching out beside the flames.

His plan was to fall asleep while his suppressants died out so he wouldn’t be awake to see Keith’s reaction. It was no secret that Shiro was an omega—albeit a rarity in the Blade—but he’d never been on duty like  _ this _ .

Keith had never experienced the full force of his...omega-ness.

Keith was silent as Shiro’s breathing evened out, occasionally stoking the cluster of low flames. The fire popped between them and Shiro shifted so his back was to Keith. The alpha wrapped a blanket around his body, curling into a ball near the warmth of the fire. He looked back to Shiro, and only when he could be certain the omega was asleep did Keith allow himself to stare. He was easily twice Keith’s size and everything about their situation deemed them incompatible.

Keith had looked up to the older Blade since joining to follow in his mother’s footsteps. Shiro had returned to active duty after losing his arm on a mission and was placed as an instructor the same year Keith decided to face the trials. Keith got to see the omega piece himself back together and become one of the strongest in their ranks.

He was Keith’s hero of sorts and they functioned well together. Jeopardizing their work with the Blade was out of the question.

Keith stared at the flames and pointedly ignoring the broad curves of Shiro’s muscular form outlined in the darkness by an orange glow. He screwed his eyes shut, wishing he could be anyone else. If only he was a few years older. Or a more dominant alpha. One that could win the affections of a warrior like Shiro.

If only.

Keith curled up inside his blanket and lost himself in thought, which proved to be a dangerous game when they turned sexual. He inhaled sharply and it was like he could taste Shiro on his tongue, his scent was so strong. The mouth-watering aroma sparked an array of images in his mind.

_ Shiro flushed beneath him. Keith’s mouth roaming over purple skin and hard muscle. Shiro slicking just for him. _

A wave of panic crashed over Keith and his gaze snapped to Shiro, needing confirmation that the omega still slept. He let out a sigh of relief as Shiro snored softly a few meters away.

Keith slumped, his body heavy, skin tingling with adrenaline at the thought of getting caught.

_ If only. _

An unbidden palm rustled beneath his blanket and dragged over his twitching length. His lids shuddered as he let himself melt back into his fantasies. It was wrong. On so many levels. But Keith couldn't’ bring himself to care as he wantonly relished in the feel of his hand stroking his cock.

Under normal circumstances, Keith’s indiscretion would go unnoticed, tucked away in the dark pocket of his blanket. But without his suppressants, Shiro wasn’t just emitting stronger pheromones. His senses were heightened. And after blinking blearily awake, he picked up on Keith’s movements, the sharp scent of his arousal, the soft moans huffed out between his teeth.

Shiro froze, keeping himself still and willing his heart to stop hammering away in his chest.

Keith was so gone in his task that he began to sigh louder, move bigger, and soon he was driving toward a climax as Shiro listened on, the omega fully aware of what was happening, his skin pulling too-tight as desire twisted raw and molten in his belly.

Shiro’s eyes drifted along the cave wall until they reached the mouth, which opened to the night sky. With his back to the flames and the alpha, Shiro tuned in to the sounds Keith made. He could hear the hitch in Keith’s breath as he increased his pace.

A ragged moan escaped him and bounced along the stone walls and suddenly Keith fell silent.

Then the alpha cursed under his breath and Shiro sat up in a bolt, looking at Keith over the fire between them.

“I’m sorry, Commander Shirogane.”

Keith’s voice cracked and he coughed as he rearranged himself, eyes looking anywhere but Shiro.

“I’m the one who should be apologizing.” Shiro’s fluffy ears tipped back, his brow furrowed and his face serious. “We’ve been in the field for a long time, erm. It’s...normal. To have.” Shiro thought he was going to burst into flames on the spot. “Urges.”

Keith swallowed. “I didn’t mean to offend you. Sir. It’s so unprofessional to have….you know.” Keith gestured between them, his words stilted. “A thing. With my commanding officer.”

“Excuse me?” Shiro felt a surprise bubble of joy pop in his chest, his long legs folding as he inspected Keith.

“You know,” Keith repeated, clearly flustered. “Masturbating to your commanding officer.”

“You were thinking about me?”

The sardonic look Keith shot him was sharper than the knife strapped to his back.

“Are you really gonna make me say it again, Shiro?”

The omega thought about letting it go. About pretending that nothing ever happened. But Keith’s admission sparked something in him and he heard himself speak. “I was thinking about you, too. I have been, I mean.”

Was this flirting? Was this what it was like to flirt with someone you shared a mutual attraction with?

Shiro scooted closer, his big body surprisingly agile and he pulled his knees up to his chest, sitting so close to Keith their feet almost touched.

“Since when… Wait, how long have you?” Shiro tried to find the words, his system flooding with hormones as his thoughts raced faster than he could articulate.

Keith slowed him with one easy grin.

“A while,” he said, leaning in to close the distance between them with a brush of his fingers along Shiro’s cheek.

The omega shivered and a purr of pure bliss rippled along his spine.

Keith laughed and it was husky and low and felt forbidden–the spark of a meteor against a black velvet sky–lighting Shiro up in all the right places. His head fell to the side, exposing the scent gland there, a sign of how much Shiro trusted this alpha.

There was a question in Keith’s eyes, and Shiro gave him a small smile of permission.

Keith’s wrist brushed against Shiro’s throat and an explosion of sensation crackled where their skin met. They surged toward one another and Keith crawled on top of Shiro, legs straddling either side of him, hands pinning Shiro’s wrists on either side of his head.

“Wait,” Shiro said, eyes darting away from Keith’s figure looming above him. “You’re almost ten years younger than me. You could have any mate you wanted. Why would you want someone like me?”

Keith leaned down, running the tip of his nose along Shiro’s bridge.

“Why would you say that?” Keith looked genuinely confused, so he filled the awkward silence between them. “Shiro you’re. Amazing. I just never thought I’d have a chance with you.”

Keith pressed light kisses along Shiro’s jaw. “I’ve had a crush on you for as long as I can remember. But I always figured you were out of my league.”

Keith’s mouth found the gland at Shiro’s throat and latched on, drawing a moan out of the omega, his body arching up against Keith.

“I’ve got you,” he whispered into Shiro’s skin.

There was a thread of vulnerability that rippled through Shiro, but he severed it, allowing himself to drift free into whatever pleasures Keith could offer.

Keith shifted so he was kneeling between Shiro’s heavy thighs. Shiro felt so wanton, and it stoked the fire within him, his body responding to the weight of Keith against his core.

“Off,” Keith said, sitting back on his heels. He said the command with some conviction but was still surprised when Shiro obeyed, leaning back to unclasp his suit and pull off the remains of his uniform. He used the bunched up material to form a pillow behind his head.

Keith hurried to match him and they returned to each other, skin on skin. Their mouths met, bodies grinding together as their hands explored, greedy and unabashed. Shiro was rock hard, rutting his hips against Keith’s compact body. He’d had his share of partners in his younger days but it had been some time since anyone had sparked his interest. And then his feelings for Keith shut off his desire to seek anyone out.

Every feeling that had been suppressed over the years erupted in fireworks across Shiro’s body. He moaned, coming alive with each pass of Keith’s fingertips, each pull of his teeth. Keith reached down between them, taking their cocks in his hand and stroking them together.

“You’re so hard,” he said. “And wet.”

Shiro whined as Keith's thumb dragged along his head.

“I always wondered what kind of omega you are. Are you loud? Are you needy? Are you sensitive?”

Keith’s voice rasped below Shiro’s ear, his mouth suckling at the tender flesh of his throat while his hands pumped faster.

Shiro keened.

“All three? I should be surprised, but I’m not. You’re always setting the bar so high, commander.”

Keith increased the pressure and Shiro cried out, his heels digging into the stone floor. His body jerked as he came hard over Keith’s fist.

“So sexy,” Keith murmured, and he licked his way down Shiro’s body, swiping a thumb through his mess and bringing it to his lips.

Seeing his leader sprawled out before him, willing and wanting, unleashing a part of Keith he’d hidden for so long. Now that he had the omega he’d been dreaming of pliant beneath his hands, he was going to draw out every moan he possibly could.

Keith nibbled and kissed his way over Shiro’s hip bones, thumbs pressing at the glands on his inner thighs. Shiro was squirming, body trembling in the aftershocks of his climax. The alpha gazed up Shiro’s body, his pulse thrumming with need as victory roared within him for pleasing his mate.

His lips parted and he swallowed Shiro down, relishing in the grunt that sounded above him. One large hand slipped into his hair and tugged, and Keith hummed in appreciation, his tongue circling Shiro’s length, lips pursed as he bobbed up and down.

Shiro watched his cock slide in and out Keith’s mouth, propping himself up with his one hand while the other tugged insistently against Keith’s scalp, his large frame curling around Keith.

Keith let the omega set the pace, relishing in the wild buck of Shiro's hips as moisture pooled at the corners of his mouth.

“Keith.”

Shiro's voice was soft and strained, his thighs quaking on either side of Keith's face. The alpha picked up his pace, working Shiro until his entire body was strung tight, bowed and begging for release. He took Shiro further, his cock hitting the back of Keith’s throat. The omega was already much larger than Keith and he relaxed against the choking pressure, drunk on the sounds and scents of Shiro whirling around him like the sweetest daydream.

But it was real.

His cock twitched between his legs as he devoured Shiro, pulling another orgasm from him with a sharp cry. Keith swallowed and shifted, bringing his teeth to one of the glands on the omega’s thigh and biting it as he rode out his orgasm.

“Keith!”

The alpha repeated the gesture on the opposite thigh, careful not to break the skin. Keith rose up above him, sitting back on his heels to inspect his work. Shiro’s lavender skin peppered with blossoming bruises, his stomach covered with sticky fluid, his massive chest heaving for breath.

Keith felt a surge of pride that he was able to do this for his mate and moved to cover Shiro’s mouth with his own. The kiss was painfully tender, Shiro purring against Keith’s lips. For a long while, they stayed just like that, their mouths communicating years of need, years of silent yearning that was now unleashed.

A sweet scent filled the cave and Shiro flushed when he realized he was slicking for Keith, moisture pooling between his cheeks and dripping onto the cave floor. His body was a puddle after Keith’s attentions, and now he looked tentatively up at the alpha, worried his neediness would be seen as the desperate attempt of an older omega to mate.

He dropped his gaze almost immediately once he read the confusion and intensity of Keith’s amethyst stare. Keith bent down to kiss him again, but Shiro turned his head to the side, panic beginning to well in his chest.

“Hey,” Keith said softly, his finger tucking beneath Shiro’s chin and pulling his eyes back up. “What’s wrong? Why are you hiding from me?”

Shiro tried to speak, but he couldn’t voice his insecurities aloud. “I just never want this to end,” he said, half-afraid at the resounding truth of his response.

Keith smiled down at him, leaving a trail of feather-light kisses along Shiro’s cheek, his strong jaw, his forehead.

“Well, that’s good. Because I’m never gonna let you go. I love you, Shiro.”

The omega’s heart ground to a halt in his chest, his breath caught in his throat as he looked up at Keith, feeling at once like he’d finally come home and opened the door to an entirely different future.

“I love you, too.”

Keith kissed him again, and there was a new heat building. Something ancient and eternal, the low flames beside them nothing compared to the blazing wildfire that spread between them. Their kisses turned almost hostile with the sheer force of need behind them. Keith plunged his tongue into Shiro’s mouth, his fingers fisting in Shiro’s hair.

The omega moaned, painfully aware that he was hard again, that his body was priming itself for Keith. His purrs turned into growls and he broke away from Keith to bite down on the flesh connecting his neck and shoulder.

Keith grunted, hips rutting forward, and Shiro lapped up the small droplets of blood that burst forth from his pale skin. Shiro’s legs fell open and Keith was there between them, his hand sliding down the omega’s body as his fingers dipped down, sliding through the slick.

“You smell so good,” Keith murmured, bringing his wet fingertips up to his face, his tongue darting out for a taste.

Shiro groaned at the sight, body twitching. Keith’s fingers returned and Shiro spread as wide as he could, granting him access to his entrance. When Keith pressed a single digit in, Shiro knew he was in trouble. He hadn’t mated in some time, mostly exploring in his younger years, but that all stopped with his accident. He’d been alone for so long, he’d forgotten the delicious stretch of an alpha’s touch.

And this was not just any alpha.

Keith’s face was perfection as it loomed about Shiro’s chest, and he couldn’t take his eyes off him as Keith began to move, dragging his finger out and slowly pushing back in. Their eyes locked as Keith worked him open, eventually adding a second finger and splitting them, the slick providing more than enough lubricant for the job.

Keith fucked him with his fingers until Shiro was quivering, a third orgasm snapping beneath Shiro’s skin.

“Keith, please,” Shiro begged, watching the glow of the fire dance along half of Keith’s face in the darkness as is illuminated him in amber light. “I want you. I don’t want to come again without you.”

“ _ Please _ ,” he growled through clenched fangs.

Keith pulled back.

“Turn over,” he said, scooting to give Shiro enough room.

Keith knew he wouldn’t last long, and with their size difference, there weren’t many positions that afforded him the leverage he wanted. It took them a moment to get situated, Shiro on his knees, facing the cave mouth, and Keith at his back. The omega was perched with his hands between his thighs, and Keith took a mental picture so he could remember Shiro’s utter perfection later.

He knelt between Shiro’s calves, his hand guiding Shiro lower as he lined himself up with the omega’s entrance. Keith nipped and kissed along Shiro’s spine as he nudged the head of his eager cock inside, their twin cries echoing around the cave.

Shiro was tight, and Keith gave him a moment to adjust before pulling back and thrusting in again, going further. The alpha’s head fell back as a groan scraped his throat. His hands found Shiro’s hips and he pushed up in one, strong thrust, seating himself to the hilt.

Keith tried to hold back, tried to keep himself from being too rough with Shiro. But the tight heat pulled him under, and he slipped almost entirely out, only to slam back in. The alpha set a torturous rhythm, his hips snapping forward in slow, brutal thrusts.

All the while, Keith murmured assurances into Shiro’s skin, telling him how long he’d waited, how badly he’d wanted this, how beautiful he was, how much he loved him. And Shiro let the words wash over him, melding with the deliquescent heat he was drowning in. His claws scraped against the stone floor as he pushed back against Keith in a silent plea for more.

Keith picked up his pace, fucking into him with savage delight, his fingers digging into Shiro’s hips with bruising force.

“I’m c-close,” Shiro said, half-lidded gaze blurring as he looked out at the stars.

The alpha grunted as their skin slapped together.

“Can you come untouched, baby?”

“Yes!” Shiro cried out, surprised and delighted at the endearment.

“Good,” Keith said, and he pulled back and hammered home with enough force to push his swelling knot inside.

The added sensation drew a ragged moan from Shiro and it only took a few more thrusts until he was coming again, his entire body convulsing with the strength of his climax.

He narrowly avoided putting out the fire, but that was more luck than anything on his part.

Shiro’s body milked Keith’s, and the alpha reached up, pulling at Shiro’s hair until he was bent backward, his neck exposed to Keith’s mouth. He was still coming when Keith’s mouth sank in, and he felt the alpha’s hips stutter, a moan reverberating against his skin as Keith followed. There was a strange tug of pressure between his legs and Keith realized his knot was sealing them together.

“Oh, shit. Sorry,” he said awkwardly. “That’s, um. That’s never happened to me before.

Shiro chuckled, his words slurred as he relaxed against Keith, completely content. “S’okay.”  

They stayed entwined for a long while, the fire slowly dying beside them.

Eventually, the knot released and Keith pulled out, watching as his seed leaked from Shiro’s entrance. He felt dirty doing it, but the alpha in him was beating its chest with victorious joy. He blew softly along the sheen of sweat dotting Shiro’s back and the omega shivered.

When they finally broke apart, Shiro sank to his side, clearly spent. Keith grinned at him, tugging his blanket over Shiro’s frame. He positioned himself at Shiro’s head, his lap proving to be an effective pillow.

Keith carded his fingers through Shiro’s disheveled hair, scratching behind one fluffy ear and relishing in the way Shiro purred against him.

“I love you,” Keith said.

“You too,” Shiro said dazedly, too exhausted and content to be a good conversationalist.

It wasn’t until much later that Shiro was able to reflect on what happened. On how they’d mated with no protection.

What would Keith say if Shiro was pregnant?

Before he could panic, he remembered Keith’s smile. His kiss. The tenderness in his gaze when he’d told Shiro he loved him. Then he thought of a child that was part him, part Keith.

Shiro fell asleep with the dream of his own family closer than it had ever been before.

**Author's Note:**

> ahhhhhh older, vulnerable Shiro pulls at my fucking heart and I hope Keith spoils himmmm~~
> 
> Thank you to Shanny and Brit for beta-reading!!! 
> 
> More trash and nonsense on my Twitter---->[@nihilistshiro](https://twitter.com/NihilistShiro)


End file.
